[vlc-devel] commit: Remove non-sensical NPT c omputation code from c9569b35. ( Rémi Den is- Courmont )

Ross Finlayson finlayson at live555.com
Tue Jul 22 22:55:33 CEST 2008

At 7:23 PM +0300 7/22/08, Rémi Denis-Courmont wrote:
>  > (Even though the times included in RTCP reports are in the Network
>>  Time Protocol (NTP) time *format*, they are not guaranteed to
>>  actually be NTP-synced times.  This is apparently what is happening
>>  with your QTSS stream, if you've found that the received presentation
>>  times are not aligned with VLC's wall clock.)
>I have to disagree. Of course, there will be an arbitrary offset between the
>RTCP timestamps, and the VLC clock. But the RTP timestamps and the VLC clock
>will increase at almost the same speed (i.e. the slope of the affine

We're actually in agreement here.  All I meant by 
the RTCP times being "not guaranteed to be 
NTP-synced times" is that they're not guaranteed 
to be the same 'wall clock' times that you'd get 
if you ran the Network Time Protocol (note the 
4th paragraph of RFC 3550, section 4), and so 
there will be an (almost constant) offset between 
these times and VLC's clock times - an offset 
that VLC needs to manage.

Ross Finlayson
Live Networks, Inc.

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